1. Field of the Invention
The present invention relates to a piezoelectric device of polymer.
2. Description of the Related Art
Although a piezoelectric or a pyroelectric polymer material is very flexible and light and the commercialization thereof has been widely applied to a flat speaker, various switches, medical sensors, aerospace and aviation materials due to its wide vibration range, but it has various limitations in usages due to its low dielectric constant and low electro-mechanical coupling coefficient.
In commercializing the piezoelectric polymer material, it is very important to form a metal electrode on a piezoelectric polymer substrate, and a quality of the piezoelectric film is greatly affected by a method used for forming the film.
As such piezoelectric polymer materials are provided with intrinsic characteristics of the polymer materials such as flexibility, shock resistance, fabrication easiness, a large-area possibility or the like, they have high power output constant (piezoelectric g constant) in comparison with an inorganic piezoelectric material; and also, since an acoustic impedance is similar to human bodies or water, they are expected to be applied to various sensors or ultrasonic transducers such as hydro phone or vibration damper (damper) or vibration generation.
Although the piezoelectric polymer having a piezoelectricity in itself of the polymer represented as the polyvinylidene fluoride (PVDF) is well known, since it has a low d constant in comparison with an inorganic piezoelectric material, the sufficient performance cannot be obtained in case of being used for the above usage.